<?php 
$chuoi = $_SERVER['HTTP_REFERER'];
$kq = strpos($chuoi,'Dang-Nhap.html');
if($kq == true)
          echo '<script type="text/javascript">
	window.location.href = "index.html";
	</script>';
else
          echo '<script type="text/javascript">
	window.location.href = "'.$_SERVER['HTTP_REFERER'].'";
	</script>';
;?>